I am sorry, but I didn't understand you very well.
If a coach is in a garbage time situation, he will pull his starters. If you know this, and you also know that you are going to be in a blowout situation, it is your responsibility to field a team that reflects this.
I am not sure whether or not GS plays a part in the substitution decision making. What's more, the coach in this game is not responsible for minute management. That is the general manager's (your) job. GS and stamina have relevance to what happens on the court during a game. Minutes played has an effect on later games so the coach isn't responsible for those things in BuzzerBeater. He only worries about what happens on the court for 48 minutes 3 times a week (or 2 or 4 or 5, depending), so it makes sense he doesn't worry about minutes played.
1) The user is responsible to spread the minutes upon setting starters and backups.
He is not responsible that the coach will use its engine-reasoning and take out tired players upon Stamina and Gam-Shape (as he already doing) and the same needs to be upon minutes along the week.
Definately in the sceanrio I've described.
2) This is exactly the difference between coaching and managing a team.
The coach is responsible to follow manager orders upon current situation on the court.
The manager is responsible to give the correct orders that implies the basic rules for that week or year.
Again, there is no reason why a coach will not use is judgement in the described scenario.
It is totaly not related to BB managing skills.
It is very similar to the fact that a player will try and take even an hard shot when the time dwindles down, although the manager asked for patient playing.
The manager is setting the rules guidelines.
The stuff (including players) are expected to follow that guideline, but to use common sense (it is even not logic. It is only common sense that even the worst coach out there has it...)